This invention relates to a mounting assembly and more particularly but not exclusively to a mounting assembly for mounting a working implement such as a loading bucket at one end of a loading arm.
Working machines are known which have one or more arms at the ends of which are mounted working implements such as loading implements. For example, typically a loading implement is a loading bucket or a pair of loading forks.
It is desirable to provide a mounting for such working implements which permits the working implement readily to be exchanged, to suit different tasks. Hence mountings commonly known as xe2x80x9cquick hitchesxe2x80x9d have been developed which enable for example, a range of different sized loading buckets to be mounted on a working arm.
It has been found undesirable to provide a working implement consisting solely of loading forks, which can be mounted directly on the arm when desired. This is because such loading forks are prone to theft and loss on building and the like sites.
Hence it has been proposed to mount loading forks on a loading bucket. Such forks are generally movable from an, in use, position in which the forks extend forwardly of the bucket, to a stowed position in which the forks are pivoted to a position above and/or behind the bucket for stowage.
Such an arrangement solves the problems of loss and/or theft of the loading forks, but the designs hithertofore proposed have presented their own disadvantages.
For example, when the forks are in use, being located in front of the bucket, visibility for a machine operator is obscured making accurate positioning of the forks for optimum lifting efficiency and safety, unreliable.
Second, because the forks extend forwardly of the bucket, the overall radius of the machine during turning is increased which can present difficulty where space is restricted. Also, the load to be lifted is positioned further from a point of connection of the arm to the remainder of the machine making lifting performance inferior and possibly reducing the specification of the machine.
Third, because the forks are used in conjunction with what may be a dirty bucket, the forks themselves may become contaminated making subsequent stowing of the forks an unpopular task.
Fourth, current designs of fork mountings on the loading bucket are such that the forks are heavy to lift to and from the stowed position, and when in their stowed position, can rattle, particularly but not exclusively when the loading bucket is in use.
Fifthly, the presence of the forks mounted on the loading bucket can restrict manipulation of the bucket and are prone to fouling of structures adjacent the working machine.
According to a first aspect of the invention we provide a mounting assembly including an arm, and a working implement mounting device provided at or towards one end of the arm, the working implement mounting device being adapted releasably to mount on the arm a first working implement, and the invention being characterised in that the working implement mounting device has mounted thereon, a second working implement, the second working implement being mounted such that the second working implement is movable relative to the working implement mounting device between a first position in which the second working implement may be used when the first working implement is de-mounted from the arm, and a second position in which the second working implement is stowed to allow use of the first working implement when mounted on the arm.
Because the second working implement e.g. loading forks, is mounted on the working implement mounting device, the risk of loss/theft of the second loading implement is minimised and thus the assembly enjoys the advantages of prior arrangements where the loading forks are mounted on a first working implement e.g. bucket. However the disadvantages associated with such prior arrangements are substantially overcome in that with the first working implement e.g. bucket, de-mounted from the arm, an operator""s vision during usage of the second working implement is not obscured, the turning radius of the machine is not increased or at least is not substantially increased, and because the load can be positioned closer to the machine, more stable lifting can be achieved, and with the absence of the e.g. bucket during use of the e.g. forks, the forks are less prone to contamination.
Also, positioning of the first working implement relative to the arm need not be compromised by the permanent presence of the second working implement on the working implement mounting device, giving more scope for designs which will not require such great effort to move the second working implement between the first and second positions as with known arrangements.
Preferably the working implement mounting device is attached to the arm by an attachment means which permits the working implement mounting device to be manipulated relative to the arm so that the working implement mounting device and working implement can be manipulated relative to the arm as one. Thus the working implement mounting device may have first mounting means for releasably mounting the first working implement, the first mounting means including an movable locking element which is movable between a locked position in which the locking element co-operates with a formation of the first working implement to mount the first working implement, and an unlocked position in which the first working implement may be de-mounted.
The working implement mounting device may have second mounting means for the second working implement, e.g. the second working implement may be pivotally mounted on the working implement mounting device for movement between the first and second positions.
The second working implement may be adapted for lifting an article, and when in the first position, a first part of the implement may engage with a support member of the working implement mounting device to prevent further downward pivoting of the second working implement during lifting. Conversely, when the second working implement is pivoted to the second, stowed, position, a second part of the implement may engage with a stop member either provided on the working implement mounting device or the first working implement, to prevent further pivoting beyond the second position.
To prevent the second working implement unintentionally moving from the stowed position, restraining means on the working implement mounting device or the first working implement may be provided to restrain the second working implement from pivoting from the second position when stowed.
In one embodiment the working implement mounting device includes a cylindrical mounting member and the second working implement includes a pair of loading members pivotally mounted on the cylindrical mounting member, and the loading members of the pair being relatively movable along the cylindrical member bar.
Each of the loading members of the pair may have first and second mutually generally perpendicular portion, the first portion being adapted to cooperate with an article to be loaded, and the second portion including a mounting portion by means of which the loading member is pivotally mounted on the working implement mounting device.
In one arrangement the second portion of each of the pair of loading members, is movable relative to the mounting portion such that when the second working implement is moved to the second position, at least a part of the first portion is located generally behind the working implement mounting device. Thus stowage of the forks is more elegant.
The second portion of each of the pair of loading members, may be pivotal relative to the mounting portion or otherwise movable.
In each case preferably the second portions of the loading members and the corresponding mounting portions have co-operating means which cooperate so that in use, at least when the loading members are loaded, relative movement between the second and mounting portions of the loading members is resisted.
According to a second aspect of the invention we provide a working implement mounting device for use in an assembly according to the first aspect of the invention, the device being adapted to have mounted thereon a second working implement.
According to a third aspect of the invention we provide a working machine having a mounting assembly according to the first aspect of the invention.